Iodinated Disinfection By-Products in Minnesota’s Water

The Minnesota Pollution Control Agency (MPCA) has been monitoring for contaminants of emerging concern in Minnesota's surface water since 2007. These contaminants include a wide variety of pharmaceuticals, personal care products, and other chemicals that can harm fish and wildlife and human health. One group of these chemicals, disinfection by-products, are formed when water is treated with chlorine. Some of these chemicals are cancer-causing and highly toxic. When wastewater treatment plants chlorinate waste water effluent to disinfect it, chemicals referred to as iodinated disinfection by-products are formed. These chemicals are of great concern due to their anticipated high toxicity to fish and wildlife in lake and river water, and to human health. They are not currently being monitored in surface water.